The present invention relates generally to the field of rotary electrical encoders. More particularly, it relates to a modular encoder and an integral switch wherein the encoder and the switch are actuated by a common shaft.
Rotary electrical encoders are well-known in the art, as exemplified by U.S. Pat. No. 4,599,605 to Froeb et al. Such devices typically include a housing that encloses a substrate having a conductive pattern formed thereon to define a preselected digital signal, in the form of a pulse train or the like. A rotor, rotated by a shaft, carries a rotating contact element that contacts the conductive pattern as the rotor is rotated to generate an electrical signal having the digital characteristics defined by the conductive pattern on the substrate.
In many electronic applications, space-saving considerations are of great importance. One approach to minimizing circuit board space requirements has been the combining of several components in a single housing, particularly in tandem relationships.
This approach has been taken, for example, in U.S. Pat. No. 4,146,758 to Hiwatahi, et al., which discloses a rotary switch having a rotor that is axially movable between two sets of stationary contacts contained in one housing.
A variation on the above described space-saving scheme is the use of stacked, modular components. U.S. Pat. No. 4,166,200 to Reichen et al., for example, discloses a modular rotary switch assembly comprising a pair of rotary switches joined together so as to be operable, either independently, or simultanenously, by a pair of concentric shafts. U.S. Pat. No. 4,518,832 to Geremia discloses a switch assembly comprising a plurality of stacked, modular switch sections, including, both rotary switches and push-pull switches, all actuated by a common central shaft.
The prior art discussed above has demonstrated the successful combination of multiple components that are functionally similar. Nevertheless, further refinements, in terms of compactness, economy of manufacture, and reliability, are in constant demand.